Over 40 percent of insect species are threatened with extinction, and total insect biomass is decreasing at a rate of 2.5 percent per year. Based on current trends, insects could be extinct within a century.

"It is very rapid. In 10 years you will have a quarter less, in 50 years only half left and in 100 years you will have none," review author Francisco Sánchez-Bayo told The Guardian.

Could we see the end of the wētā?
Photo credit: File

And there will be no escape for New Zealand. Local bug expert Ruud Kleinpaste warns that if they go, the results would be "catastrophic" and we would have "no hope in hell of surviving".

"In the worst case scenario we might not be able to grow much food," he told Newshub.

"You go and take them out and all these things are falling over like a house of cards."

Insects are everywhere, doing "extremely important" jobs in New Zealand's ecosystem we normally take for granted. We rely on them for our agriculture, to remove animal waste and bodies, and to feed other creatures.

"They do pest control. Keep the balance between species. They're the base of the food chain, which affects all predators."

In their absence, things would turn into - literally - an "absolute shitmess" as animal dung piles up.

"Do you know how much shit we get from cows, sheep, horses? And who cleans it up? Insects," he says.

"If there's no dung removal insects, what do you do with all that? It lies there. It means the soil is covered in dung."

A dung beetle.
Photo credit: Supplied

The main cause of insect losses has been blamed on agricultural intensification, and the use of pesticides and herbicides.

"That means the elimination of all trees and shrubs that normally surround the fields, so there are plain, bare fields that are treated with synthetic fertilisers and pesticides," study author Mr Sánchez-Bayo told The Guardian.

"Industrial-scale, intensive agriculture is the one that is killing the ecosystems."

There isn't enough data on the health of New Zealand insects, but Mr Kleinpaste warns our native species are under pressure. He's calling for more research into the health of insect species in New Zealand and wants Kiwis to focus on creating a more sustainable way of life.

"We need to rediscover the operations manual of planet earth," he says.

"So we live in harmony with nature and then we understand how to rectify the problems we've caused."

The study authors agree, warning that if insect species losses cannot be halted, "this will have catastrophic consequences for both the planet's ecosystems and for the survival of mankind".

"The bigger picture is, this would be catastrophic," Mr Kleinpaste warns. "We're making serious mistakes."